Magnetic drafting system test apparatus



MAGNETIC DRAFTING SYSTEM TEST APPARATUS W. N. LILLY I Dec. 17, 1968 Filed Oct. 22, 1965 FIG.!

. INVENTOK' WILLIAM N. LILLY Attorney United States Patent 3,416,368 MAGNETIC DRAFTING SYSTEM TEST APPARATUS William N. Lilly, Greensboro, N.C., assignor to Cone Mills Corporation, Greensboro, N.C., a corporation of North Carolina Filed Oct. 22, 1965, Ser. No. 501,540 3 Claims. (Cl. 73141) ABSTRACT OF THE DISCLOSURE An apparatus for testing the magnetic strength of magnetized top rolls of a spinning machine drafting element while these rolls are retained in their normal operating position having a support member carrying magnetically responsive means to hold the apparatus against the top roll. An adjustable lever arm permits the apparatus to be varied for testing top rolls of differing magnetic strengths for insuring that all tested top rolls are of at least a minimum magnetic strength.

In the drafting element of conventional spinning machines, a series of spaced-apart positively driven rolls are conventionally mounted to rotate about fixed shafts that are maintained in a desired operating position by collars and bearings so that the slightly twisted strands of fibers which make up the roving may be passed through guides and beneath and through the successively spaced rolls to rearrange the formation of the fibers and to increase substantially the length of the roving until a final desired yarn strand is achieved. The rolls are usually rigidly secured in place and are not easily removable for replacement or repair.

Decided improvements in driving and driven roll construction have resulted in the use of magnetic drafting systems, these systems using roll-contained magnets and the resulting magnetic force to achieve top roll weighting as particularly embodied in the MagneDraft drafing system manufactured and sold by Saco-Lowell Shops. The particular structunal configuration of a MagneDraft system comprises a magnet inside each of the top roll barrels which is attracted to a corresponding positively driving bottom steel roll, and the magnetic attraction therebetween provides consistent pressure to stock or roving passing between the rolls. The MagneDraft system has been and is widely used throughout the textile industry.

It becomes necessary, due to the continuous operation of the drafting system and inadvertent vibrations and shocks that might affect the strength of the magnetic roll that these units be periodically inspected to ascertain the level of magnetism present in order that consistent pressure be maintained by the top roll unit against the corresponding lower positively driving steel roll. The magnetic rolls are usually uniformly magnetized at a preselected strength by conventional means in order to insure consistency of pressure, but because of the many variables that might alfect that magnetic strength, periodic tests and inspections are necessary to insure reliable operation.

Existing test units require the removal of the top rolls from their normal operating position in order to accurately calculate and measure the magnetic holding strength of the particular unit under consideration, and after the test has been completed, it then must be repositioned precisely in its operational position for subsequent use. This requires a considerable amount of time for the removal and replacement of these units since the operating position setting is critical and must be carefully considered and defined when the roll units are replaced.

The present invention is directed to testing magnetic top rolls such as used in the MagneDraft system by an ap- 3,416,368 Patented Dec. 17, 1968 "ice paratus that does not require the removal and subsequent replacement of each individual roll as it is being tested. In operation, the present invention need merely be placed on a roll for testing while that roll is in its normal operating position, and if the magnetic strength of the roll is sufficient to withstand the moment of force created by a lever arm-maintained weighted sleeve, the test apparatus will not be displaced or moved from its set position and the apparatus may then be removed and the next magnetized roll unit considered. If the magnetic attraction between the top roll and the bottom steel roll is not of the desired level, the top roll then does not possess sufiicient magnetic strength to meet the inspection requirements then the testing apparatus will pivot or move with respect to that roll because of the absence of an attraction suificient to resist the created moment resulting from the weighted sleeves position on the apparatus lever arm.

Leverage is increased by sliding the weighted sleeve away from the point of contact between the apparatus and test roll, and the point along the lever arm at which the magnetic force is broken, as evidenced by the movement of the apparatus with respect to the test roll, marks the relative magnetic strength of the roll which can be calibrated and calculated in terms of actual magnetic strength. When a minimum tolerance strength has been determined through experimentation or operational procedure, the weighted sleeve can be locked with a thumbscrew or other suitable means and the individual rolls can be tested very rapidly in a simple manner by an experienced operator.

It is therefore an object of the present invention to provide an apparatus for determining the relative magnetic holding strength of magnetized rolls to bottom driving steel rolls without removing the magnetized rolls from their normal operating position.

Another object of the present invention is to provide an apparatus for determining the relative magnetic holdv ing strength of magnetized rolls to steel rolls that can be preset for rapid, repetitive operation without repositioning the calibrated weight after each operation.

Still another object of the present invention is to provide an apparatus of the type described which will not affect the operating position of the magnetized roll during the test operation.

Yet another object of the present invention is to provide an apparatus of the type described that is adapted for testing a wide variety of sizes of magnetized rolls without the necessity of any structural change.

Yet still another object of the present invention is to provide an apparatus of the type described that is extremely simple and economical in construction and requires a minimum of maintenance or repair.

Still a further object of the present invention is to provide an apparatus of the type described that will quickly, accurately and visually indicate whether or not a magnetized roll meets specific operating standards and will allow successive and immediate testing of a plurality of magnetized rolls in a much shorter time than heretofore required. 1

With the following objects and others which will appear in the following full description in mind, the invention consists in the combinations and arrangements of parts and details of construction which will now first be fully described in connection with the accompanying drawings, wherein like characters of reference designate corresponding parts throughout the several views, and then more particularly pointed out in the appended claims.

In the drawings:

FIG. 1 is a partial cross-sectional, end elevational view of a conventional spinning machine illustrating the placement of the drafting element and the positioning of the various drafting rolls with respect to the creel supporting bobbins of roving;

FIG. 2 is an enlarged, perspective sectional view of the drafting element of the spinning machine shown in FIG. I particularly illustrating the top magnetized rolls and the bottom driving steel rolls together with the placement or positioning of the testing apparatus with respect to one roll which is shown by hidden or invisible lines; and

FIG. 3 is a perspective, enlarged and sectional view of the testing apparatus herein described and its positioning with respect to a top magnetized roll under testing conditions.

Referring now to the drawings and particularly of FIG. 1, there is shown a spinning machine generally designated having a creel 12 and a plurality of bobbins 14 wound with roving 16, the bobbins being supported by holders 18 which allow adjustable positioning of these units as needed. The roving 16, which is made up of strands of fibers with just enough twist to hold them together, extends from the bobbins 14 through a guide member 20 and downwardly into and through subsequent guides 22 immediately preceding the drafting elements generally designated 24.

Drafting element 24 comprises back rolls 25 including an upper magnetized roll 26 and a bottom steel roll 28 which positively engages the closely adhering top roll 26 and rotates that roll according to the speed of its own rotation. The bottom roll 28 is usually made of steel and has helical flutes 29, and the top roll has contact surfaces covered with cots 31 of rubber or of a resilient synthetic material which will securely and positively maintain the strands of roving 16 passing therethrough. A series of middle rolls and 32 and front rolls 34 and 36 are critically spaced following the back rolls 26 and 28 and are driven at differing speeds so that the roving may be drawn into a finer elongated yarn strand by the subsequent middle and front rolls rotating at increased speeds. Thus, as the bottom rolls 28, 32 and 36 revolve, the top rolls 26, 30 and cling to and revolve with these rolls as a result of magnetic attraction while exerting a constant pressure on the roving or yarn strand that is passing between these rolls.

Once the roving has been sufliciently extended and elongated by the drawing technique of the back, middle and front rolls, it is twisted and wound on a spool 38 by a traveler 40 in a conventional manner.

The testing apparatus embodied in the present inventive concept is particularly illustrated in FIG. 3 and comprises a U-shaped support member generally designated 42, this member including a body portion 44 extending at least for the axial length of a roll to be tested and side wall portions 46 and 48 which are integral with and perpendicular to body portion 44. This U-shaped member 42 is preferably formed of a non-ferrous material so as to be unaffected by the magnetic strength of the magnet (not shown) held within the barrel portion 49 of a magnetic roll such as those designated 26, 30 and 34. A first rod 50 is disposed between side wall portions 46 and 48 and extends substantially parallel to body portion 44. This rod is retained or held at its ends 51 and 53 by suitable means to the side wall portions 46 and 48, and this rod is usually formed of a ferrous material so as so be positively attracted by the magnetic strength of a roll to be tested. A second rod 52 is also held at its ends 55 and 57 by side wall portions 46 and 48 of support member 42 and is positioned substantially parallel to rod 50 and body portion 44 of member 42. Rod 52 is also usually formed of a ferrous material so as to be attracted by the magnetic force of a magnetized roll and cooperate with rod 50 to hold the support member 42 and its carried components securely in place. Rod 52 additionally functions as a fulcrum or pivot point, its particular application being more particularly described subsequently.

A lever arm generally designated 54 is secured at one end 56 to body portion 44 to support member 42 by conventional means 58 to maintain that arm in a cantilevered or extended relationship from member 42. A weighted sleeve 60 is slidably positioned on lever arm 54 for movement along the axial length of that member so that it may be moved at will by an operator desiring to test any number of magnetized top rolls of varying magnetic strength. Securing means such as a thumbscrew 62 are used to retain sleeve 60 at a fixed position for rapidly and sequentially testing a plurality of rolls maintained at the same magnetic level. Lever arm 54 is generally formed of a non-ferrous material such as aluminum so as to be unaffected by the magnetic strength of the roll under test. Aluminum has the additional advantage of being oflight weight, and thus lever arm 54 is much more sensitive in operation than would be the case were it formed of a heavier material.

The principle of operation of the test apparatus involves the creation of a moment of force about pivot rod 52 generated by the positioning of weighted sleeve 60 along the axial length of lever arm 54 so that when the magnetic holding strength of a magnetized roll attracting the test apparatus positioned thereon is overcome, the apparatus will rotate or pivot about rod 52 since the moment of force created exceeds the magnetic attraction for maintaining that apparatus in its seated or original position. Leverage is increased by sliding the weighted sleeve 60, which is of a preselected weight, away from the pivot rod 52 along the axial length of lever arm 54. The point along lever arm 54 at which the magnetic force is broken marks the relative magnetic strength of the magnetized roll which can be calibrated and calculated in terms of the actual magnetic strength or force of the magnetized roll. Calibrations 64 along the axial length of arm 54 represent predetermined increments of calculated force so that an operator may quickly ascertain the force required to overcome the magnetic attraction of a magnetized roll for the test apparatus and the equally attracted bottom roll such as those designated 28, 32 and 36.

When a minimum tolerance magnetic strength has been determined for the magnetized rolls in operation through experimentation and analysis, the weighted sleeve 60 can be secured or locked by thumbscrew 62 or other suitable means at a predetermined position or calibration 64 along the axial length of lever arm 54 so that a plurality of rolls can be sequentially tested in a simple and expeditious manner. The operator will merely seat the testing apparatus contiguous the roll to be tested and release the lever arm 54; If the roll under test meets the minimum tolerance conditions, its magnetic force will resist the moment of force generated by weighted sleeve 60 along the lever arm 54 and the test apparatus will not pivot or rotate about pivot rod 52 or will not move in any manner independently of or with respect to the magnetized roll. If the strength of the roll under test does not meet the minimum tolerance requirements, the moment of force created by the weighted sleeve 60 positioned on arm 54 will exceed the magnetic attraction of the magnetized roll for the testing apparatus (and bottom roll), and the apparatus will pivot or rotate about rod 52 or it will slide or move relative to or independently of the magnetized roll being tested.

The rapidity with which magnetized rolls can be tested using the present inventive concept greatly exceeds any heretofore known and offers the obvious advantages of testing all magnetized rolls while they are in their normal operating position thus alleviating difficulties in replacing those magnetized rolls once they have been removed for separate and isolated testing.

Thus, there has been described a novel and highly efficient test apparatus for determining the relative magnetic holding strength of magnetized rolls to steel rolls without removing these rolls from their normal operating position. Obviously, many modifications and variations may be made in the construction and arrangements of the U-shaped support member and their carried ferrous rods as well as the lever arm and weighted sleeve as well as other phases of the present inventive concept in light of the above teachings without departing from the real spirit and purpose of this invention. Such modification of parts and alternatives as well as the use of mechanical equivalents to those herein illustrated and described are reasonably included and modifications are contemplated.

What is claimed is:

1. An apparatus for testing the magnetic holding strength of magnetized top rolls of a spinning machine drafting element against positively driven bottom rolls without removing the top rolls from their normal operating position comprising: a U-shaped support member; a first magnetically responsive rod secured to said member; a second magnetically responsive pivot rod parallel to said first r-od retained by said support member; a lever arm secured at one end to said support member; a weighted sleeve slidably disposed about said lever arm; and means releasably securing said sleeve at a preselected and calibrated position on said lever arm, said sleeve pivoting said lever arm, support member and first rod about said pivot rod when the magnetic attraction between said top roll and said first rod is overcome by the force moment elfected by said sleeve.

2. An apparatus for testing the magnetic holding strength of magnetized top rolls of a spinning machine drafting element against positively driven bottom rolls without removing the top rolls from their normal operating position comprising: a support member having a body portion and side wall portions integral with said I body portion, said body portion at least equal to the length of the roll to be tested; a first ferrous rod held by said side wall portions substantially parallel to said body portion; a second ferrous pivot rod held by said wall portions substantially parallel to said first rod and said body portion; a lever arm of selected length substantially perpendicular to said rods and secured at one end to said body portion; a weighted sleeve slidably disposed about said lever arm for movement along said length; and means releasably securing said sleeve at a preselected and calibrated position on said lever arm, said weight urging said lever arm and said support member about said pivot rod to exert a predetermined force against the magnetic attraction between said first ferrous rod and said top roll.

3. An apparatus for testing the magnetic holding strength of magnetized top rolls of a spinning machine drafting element against positively driven bottom rolls without removing the top rolls from their normal operating position comprising: a U-shaped support member having a length at least equal to the length of the roll to be tested; 'a first ferrous rod secured to said member; pivot means retained by said member; a lever arm perpendicular to said rod and secured at one end to said support member; a weighted sleeve slidably disposed about said lever arm; and means releasably securing said sleeve at a preselected and calibrated position on said lever arm, said apparatus being held to said top roll by the magnetic attraction of said top roll until the attraction is overcome by said sleeve urging said lever arm about said pivot means.

References Cited UNITED STATES PATENTS 1,260,869 3/1918 Carlson 73141 1,296,932 3/1919 Dodge 73141 2,637,115 5/1953 Watson 33174 2,750,561 6/1956 Gross 32434 2,906,118 9/ 1959 Beyland 73141 3,168,760 2/1965 OlCott 19272 RICHARD C. QUEISSER, Primary Examiner.

CHARLES A. RUEHL, Assistant Examiner.

US. Cl. X.R. 

